1. Field of the Invention
The invention relates to oil field technology, particularly in the drilling of production oil well apparatus. Although not limited to any particular location of use, the invention has particular utility at locations of drilling along the continental shelf, where environmental problems are particularly acute when oil base drilling muds are employed.
2. Disclosure Statement
U.S. Pat. No. 3,693,951, issued Sept. 26, 1972, to Lawhon et al, discloses a method and apparatus for treatment of well cuttings where a conveyor belt moves the cuttings through a preheater for partial drying, followed by treating in a high-intensity infrared heating chamber in which all volatile material is expelled from the cuttings. However, the Lawhon device requires a source of electricity and does not lend itself to high temperature use at which entrapped hydrocarbons in rock fragments, such as are particularly found between layers of cuttings derived from shale formations, can be successfully removed. U.S. Pat. No. 4,139,462, issued Feb. 13, 1979, to Sample, Jr., discloses a method for removing volatile materials from drilled cuttings by vaporizing the materials in an oxygen-free atmosphere at a relatively low temperature. Other patents relating to the field include the following:
U.S. Pat. No. 3,707,129--Dec. 26, 1972--Kawashimo et al. PA1 U.S. Pat. No. 3,693,733--Sept. 26, 1972--Teague PA1 U.S. Pat. No. 2,171,535--Sept. 5, 1939--Berg et al. PA1 U.S. Pat. No. 3,766,866--Oct. 23, 1973--Krumm PA1 U.S. Pat. No. 4,116,136--Sept. 26, 1978--Mallek et al.
Nickel-chromium alloys have been disclosed as high-temperature corrosion-resistant materials, such as in U.S. Pat. No. 4,137,074, issued Jan. 30, 1979, to Firnhaber, U.S. Pat. No. 3,859,060, issued Jan. 7, 1975, to Eiselstein et al, and in U.S. Pat. No. 3,816,110, issued June 11, 1974, to Shimotori et al. However, no teaching of corrosion and erosion resistance under the combination of high temperature, abrasiveness of rock fragments, and corrosive vapors present in a heating apparatus of the present invention exists.